   (signal-deps [s] "returns the set of \"parent\" signals on which this signal depends")
   (parents-map [s])
   (kids-map [s])
-  (topsort [s])
-  (-get-graph-meta [s k]))
+  (topsort [s]))
 
 (defn signal?
   "returns `true` if the argument satisfies `SignalProtocol`, `false` otherwise"

                (when (= relayed-topic (topic event))
                  (fresh (value event)))))
    opts))

(defn- setup-metadata
  [sig]
  (with-meta sig (->SignalDefinitionMetadata (atom nil) (atom nil) (atom nil))))

(defn make-signal
  "Takes a map of opts and returns a signal."

    (into #{}
          (filter signal?)
          (or deps sources)))
  (parents-map [s] (-> s meta :parents-map deref))
  (kids-map [s] (-> s meta :kids-map deref))
  (topsort [s] (-> s meta :topsort deref)))

(defn- setup-event-relay
  "Takes a topic, and returns an input signal which relays matching events as messages to its children"
